1. Field of the Invention
The invention relates to sound amplifiers and, more particularly, to such amplifiers having tone volume compensation.
2. Description of the Prior Art
Circuits with an amplification increasing as the frequency decreases can be used in 1f-amplifiers for effecting the frequency-dependent peaking in the case of low frequencies, especially in cases where the physiological frequency-dependent loudness perception of the human ear is to be compensated for by a corresponding oppositely oriented frequency dependence of the 1f-amplifier.
From the German Offenlegungsschrift (DE-OS) No. 27 15 981, especially from FIG. 4 thereof, there is known a bass boosting integrated circuit in which a transistor is used which is operated as an emitter follower, with this transistor indicated therein by the reference numeral 88. The base of this transistor is grounded with respect to a.c. voltage via a capacitor applied to the zero point of the circuit (ground).
Considerations and investigations of the inventor have shown that this conventional circuit only very insufficiently meets the intended purpose of a bass boosting.